• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.127-135
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• 1978

For improvement and new design of tillage equipments, indoor test is very useful and more desirable than outdoor because the experiment of outdoor is very difficult and its cost is expensive. This study was carried out to determine the physical properties of artificial soil suitable for the indoor test with the soil bin manufactured at the workshop of the Dept. of Agricultural Machinery Engineering. The artificial soil being studied was made with very similarity to the natural soil of the experimental plots of Chungnam National University, and it consist of 39.35 percent, by weight of bentonite and 48.10 percent of sand with 12.55 percent of SAE 10W oil. The results are summarized as follows: 1. Bulk density increased with increasing number of rolling, and its relationship could be expressed. $y=1.073200+0.070780x-0.002263x^2$ where, y=bulk density ($g/cm^3$), x=number of rolling. These results could be explained that the effect of rolling velocity on the bulk density was not singnificant in the range of 4.5~10.4 em/sec. 2. The absolute soil hardness depended directly upon number of rolling, and their relationship could be expressed by the equation. $y=37.74(0.64 +0.17x-0.0054x^2)/(3.36-0.17x-0.0054x^2)^3$. where, y=absolute soil hardness($kg/cm^3$), x=number of rolling. 3. Relationship between the bulk density and absolute soil hardness could be expressed by the equation; $y=37.74(2.46x-2.02)/(6.02-2.46x)^3$. where, y=absolute soil hardness, x=bulk density. 4. The cohesion and the angle of internal friction of artificial soil were increased with increasing its bulk density. According to the cohesion and angle of internal friction, at the range of 1.60~1.75 ($g/cm^3$) of bulk density, this artificial soil was similar with sandy loam of 29.5% moisture content of natural soil. 5. Sliding-fricfion coefficient of steel plate on the artificial soil was 0.3~0.4 and rubber plate on it is 0.64~0.72. Those values were very similar with those of natural soil being studies by many others.

• The Korean Journal of Nuclear Medicine Technology
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• v.19 no.1
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• pp.51-56
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• 2015

Purpose As medical radiation exposures on patients are being social issues an interest in a relief of radiation exposures on patients is increasing. Further, there are many cases where some patients among who are getting PET/CT tests choose to get implanted with metal artifacts in their bodies. This study is to find out effects of presence or absence of metal artifacts when dose change or CT attenuation correction for the relief of radiation exposures are applied using phantoms through changes in standard uptake value (SUV). Materials and Methods GE company's Discovery 710 machine was used for PET/CT test equipments. We used NEMA IEC body phantoms. We also used screw and mesh cage made of titanium which are used in real clinical processes for the metal artifacts. Two experiments were conducted: One is to test and measure repeatedly about SUV about differences in CT attenuation corrections according to dose changes and another is to do the same procedure for SUV about the presence and absence of the metal artifacts. We injected $^{18}F-FDG$ into NEMA IEC body phantoms with a TBR ratio of 4:1 and then put the metal material into the transformation phantoms. Once a scanning for the metal artifacts was done we eliminated the metal artifacts and went on non-metal artifacts. For the each two experiments, we scanned repeatedly with CT kVp (140, 120, 100, 80) and mA (120, 80, 40, 20, 10) for an experimental condition. For PET, we reconstructed each with standard AC (STD) technique and quantitation achieved cnsistently QAC) technique among CT attenuation correction methods. We conducted a comparative analysis on measured average values and variations which were measured through repeated measure of SUV of region 1, 2, 3 spheres for each conditions of non-metal /metal scan. Results For each kVp, 120, 80, 40 (mA) of non/metal (screw, mesh cage) showed low frequency of fluctuation rates of above 2%. In 20, 10 mA above 2% of fluctuation rates appeared in high frequency. Also, when we compared the fluctuation rates of STD and QAC techniques in non/metal (screw, mesh cage) tests QAC technique showed about 1-10% of differences for each conditions compared to STD technique. In addition, metal types did not have significant effects on fluctuation rates. Conclusion We confirmed that SUV fluctuation rates for both STD and QAC techniques increase as dosage is lower. We also found that the SUV of PET data was maintained steadily in a low dosage for QAC technique when compared with STD technique. Hence, when the low dosage is used for the relief of radiation exposures on patients QAC technique may be exploited helpfully and this could be applied in the same way for patients with metal artifacts implanted in their bodies.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.1
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• pp.1604-1615
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• 1969

This experiment was carried out as one of the basic studies to improve the acid resistance of concrete and it was conducted to investigate some relations among physical properties such as basorption, ratio of water to cement, compressive strength, density and ratio of mix to weight losses of mortar when exposed to 0.1 N solution of hydrochrolic acid. The results obtained from the limited data secured so far in this experiment are summarized as follows: 1. The specimens used in the experiment were made of 5 cubic centimeters of mortar having such various ratios of mix by weight as 1 : 1, 1 : 3, 1 : 5, 1 : 7, 1 : 10. 2. Physical tests included compressive strengths at 7 days, 28 days, 3 months, and 6 month, and 5 hour boiling absorption test. 3. In acid test, every specimen was immersed into 0.1 N solution of hydrochrolic acid. The specimens exposed to the acid solution were weighed to determine the weight losses of the acid-corroded at one week interval for 7 weeks exposure, and the old acid solutions were also changed to fresh one when weighed the weight losses by acid attack at one week interval. 4. The correlative relations were found among physical properties and they are expressed by certain formulas as follows; i) Relation between ratio of mix and absorption Y = 1.036x + 13.53 where Y: absorption(%) X: ratio of mix ii) Relation between ratio of mix and ratio of water-cement Y = 0.204x + 0.214 where Y: ratio of water-cement. X: ratio of mix iii) Relation between ratio of water-cement and absorption Y = 5.01x + 12.53 where Y: absorption(%). X: ratio of water-cement iv) Relation between density and absorption Y = 50.6 - 0.0176X where Y: absorption(%). X: density($kg/m^3$) v) Relation between density and ratio of water cement Y = 7.2183 - 0.0033X where Y: ratio of water-cement . X: density($kg/m^3$) 5. After completing the acid exposure test the specimens were corroded and , the per cent ranges of weight losses varies from a minimum of 20.4 per cent at a 1 : 1 mix to a maximum of 92.0 per cent at a 1:10 mix 6. The correlative relations of physical properties of mortar to weight losses by acid attak were found and they are also expressed by certain formulas as follows: i) Relation between weight losses and ratio of mix Y = 8.59X + 8.63 where Y: weight losses(%), X: ratio of mix ii) Relation between wieght losses and absorption Y = 0.121x + 12.43 where Y: absorption(%). X: weight losses(%) iii) Relation between weight losses and ratio of w/c Y = 0.0226X + 0.07 where Y: ratio of w/c X: weight losses(%) iv) Relation between weight losses and compressive strength LogY = 3.6097 - 0.05058X + 0.00022$X^2$ where Y: compressive strength ($kg/cm^3$) X: weight losses(%) v) Relation between weight losses and density Y = 2153.1 - 6.62X where Y: density($kg/m^3$) X: weigh losses(%) 7. In order to make better acid resistant mortar, it could be concluded that a 1 : 3 mix or richer mixes, adequate mixing water to minnimize the ratio of water-cement considering the workability, 16 per cent or less absorption by 5 hour boiling water, 1,800 kilogram per cubic meter or denser density by absolute weight base and 200 kilogram per square meter or compressive strength at 20 day, etc are required so as to obtain acid-resistant mortar. In addition to the above, it might be recommonded to select the fine aggregate and to use better equipments such as a mechanical vibrator, a mechanical mixer etc. in concrete manufacturing works.

• Journal of Korean Home Economics Education Association
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• v.19 no.1 s.43
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• pp.81-97
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• 2007

This study investigated the Present status of laboratories for experiment and practice, and analyzed teachers' recognitions on experiment and practice for Home Economics area of a Technology and Home Economics curriculum according to majors of teachers. Questionnaires were mailed to middle school teachers who taught home economics part and they answered on the web. 220 replies were used for the final analysis. The findings were as follows: First, the facilities and teaching equipments of laboratories for home economics area were inferior, especially, for clothing and textiles part and housing part. Second, teachers recognized necessity to conduct experiment and practice highly. Food life part scored the highest, while housing part scored the lowest. Teachers who majored in home economics recognized more necessities of experiment and practice than teachers who didn't majored in home economics. Third, they recognized level of experiment and practice to be suitable to students, but 'maintenance and repair of housing' section was relatively less suitable than other sections. Fourth, 'making clothes and recycling' section was recognized to have the least suitability in quantities and hours of experiment and practice lesson, because of too much contents and lack of lesson hours. Fifth, teachers recognized that students were more interested in 'the basis of food preparation and practice' section, but they are less interested in 'maintenance and repair of housing' section. Sixth, teachers recognized that contents of experiment and practice were very useful to the real life. 'The basis of food preparation and practice' section was the most useful, while 'maintenance and repair of housing' section was the least useful. Seventh, experiment and practice lessons for food life part were put in practice very well, followed by the order of clothing and textiles part and housing part. Teachers who majored in home economics usually took more experiment and practice lessons than teachers who didn't major in home economics.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.10-16
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• 2009

Purpose: As the number of patients has increased since the installation of a PET/CT, we are now examining about 2500-3000 annually. We have realized that if we properly adjust a pitch under the same condition of a CT during a PET/CT exam, radiation quantity that reaches the patient can change. In order to reduce the exposure dose of a patient, the research examines a method of reducing the exposure dose of a patient by controlling the pitch during a PET/CT exam, viewing whether the adjustment of the pitch influences CT image and PET SUV. Methods: The equipment used is a Biograph Positron Emission Tomography (PET) Scanner (CT type: TRCT-240-130 (WCT-240-130)) of Siemens company. For the evaluation of exposure dose of a patient, we measured radiation quantities using a PTW-DIADOS 11003/1383, which is a CT radiation measurement instrument used by Siemens. We measured and analyzed the space resolutions of CT images caused by the change of pitches using an AAPM Standard Phantom in order to see how the adjustment of pitches influenced the CT images. In addition, in order to obtain SUVs caused by each change of pitches using a PET source made with a solid radioactive cylinder phantom, we confirmed whether the SUVs changed in the PET/CT images by calculating the SUVs of the fusion images caused by the change of pitches after obtaining CT and PET images and finishing the test. Results: 2slice CT scanner showed that radiation quantities largely dropped when pitches ranged from 0.7 to 1.3 and that the reduction of radiation quantities were smaller when pitches ranged from 1.5 to 1.9. That is, we found that the bigger pitch values are the smaller the radiation quantities of a patient are. Moreover, we realized that there is no change of SUVs caused by the increase of pitches and that pitch values do not influence PET SUVs and the quality of CT images. It is judged that using 1.5 as a pitch value contributes to the reduction of exposure dose of a patient as long as there is no problem in the quality of an image. Conclusions: When seeing the result of the research, hospital using a PET/CT should make an effort to reduce the exposure dose of a patient seeking pitch values appropriate for their hospital within the range in which there is no image distortion and PET SUVs are not influenced from pitches. We think that the research can apply to all multi-detectors having a CT scanner and that such a research will be needed for other equipments in the future.

• Journal of dental hygiene science
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• v.16 no.4
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• pp.284-292
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• 2016

Water supplied through dental unit waterlines (DUWLs) has been shown to contain high number of bacteria. To reduce the contamination of DUWLs, it is essential to develop effective disinfectants. It is, however, difficulty to obtain proper DUWL samples for studies. The purpose of this study was to establish a simple laboratory model for reproducing DUWL biofilms. The bacteria obtained from DUWLs were cultured in R2A liquid medium for 10 days, and then stored at $-70^{\circ}C$. This stock was inoculated into R2A liquid medium and incubated in batch mode. After 5 days of culturing, it was inoculated into the biofilm formation model developed in this study. Our biofilm formation model comprised of a beaker containing R2A liquid medium and five glass rods attached to DUWL polyurethane tubing. Biofilm was allowed to form on the stir plate and the medium was replaced every 2 days. After 4 days of biofilm formation in the laboratory model, biofilm thickness, morphological characteristics and distribution of the composing bacteria were examined by confocal laser microscopy and scanning electron microscopy. The mean of biofilm accumulation was $4.68{\times}10^4$ colony forming unit/$cm^2$ and its thickness was $10{\sim}14{\mu}m$. In our laboratory model, thick bacterial lumps were observed in some parts of the tubing. To test the suitability of this biofilm model system, the effectiveness of disinfectants such as sodium hypochlorite, hydrogen peroxide, and chlorhexidine, was examined by their application to the biofilm formed in our model. Lower concentrations of disinfectants were less effective in reducing the count of bacteria constituting the biofilm. These results showed that our DUWL biofilm laboratory model was appropriate for comparison of disinfectant effects. Our laboratory model is expected to be useful for various other purposes in further studies.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.628-634
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• 2008

In recent years, cross-contamination has become one of the noticeable issues in dental clinic. Two major routes of contamination are the direct-contamination through blood and oral secretion and the indirect-contamination through dental office equipments. Especially, air-contamination through air-floating pollutant in a confined space like hospital, and also contamination through aerosol ejected from high-speed handpiece in a dental office was interested. The purpose of this study was to understand risk of bacterial infection through aerosol from handpiece in a dental office, which will help the practitioner with prevention of contamination during dental treatment. The main findings are as follows. 1. In a comparative test, the group using handpiece has higher bacterial number than the group not using handpiece with significant statistical difference(P<0.01). 2. The group using handpiece with rubber dam has lower bacterial number than the group using handpiecewithout rubber dam with significant statistical difference(P<0.01). 3. Comparing the group using drainage water with the group using distilled water as a handpiece water source results in 22.4 cfu and 17.0 cfu respectively but the difference is no statistically significant(P>0.05). 4. Measuring cfu at 0.5m and 1.5m distance, 0.5m distance showed higher bacterial number with statistical significance(P<0.01). 5. Classification of bacterial types showed the largest bacterial number came from gram-positive micrococcus(73.9%), and gram-negative micrococcus, gram-negative bacillus, and gram-positive bacillus follow in descending order.

• Korea Journal of Hospital Management
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• v.8 no.1
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• pp.112-134
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• 2003

The purpose of this study is to analyze the consumer's expectation before the health care service and the consumer's satisfaction after it. The participants of the study are inpatients in a general hospital located in Seoul. The resources were collected from the self-administration questionnaire survey run parallel with face to face interview. In order to measure the degree of the consumer's expectation, 349 samples were collected from the first questionnaire survey on the date of admission to the hospital. The second questionnaire survey was carried out on the date of discharge to the hospital with the participants responding to the first questionnaire survey. There are 154 samples collected from this survey. The results from the analysis of these resources are as follow. First, the survey shows that one of the highest consumers' expectations was about the generosity, kindliness and sincerity from the staff at the hospital, specially from doctors. Second, according to the analysis of the factors affecting the expectations of the consumers, with regard to path of admission to a hospital relating to patient's features, outpatient who gets into a hospital expected good medical care much more than the other patients. In regard of doctor's features, patients usually and highly expect good medical care from doctors who have good carrier and much experience. Third, according to the second questionnaire survey, what patients are satisfied most with is about the generosity and sincerity from staff at a hospital, especially from doctors and their gem attitudes. The results from survey show that the differences among the degree of consumers' satisfaction are very variable, depending on surrounding environments and facilities. The only fact that expectation didn't meet with satisfaction appeared to the case about technology and skill of medical care and the case about updated medical skills and equipments. Fourth, comparing the degree of expectation with the degree of satisfaction of consumers, correlative analysis was concerned significantly and specifically about the part of overall cleanliness relating to facilities and surrounding environments, the items about medical examination and test plan procedure relating to skill of medical care, professional specialties and convenience for procedure, and the items about satisfying explanations and concern about patients from doctors relating to staff's generosity and sincerity. Fifth, the analysis of the factors affecting the degree of how much patients are satisfied with shows that relating to sociodemographical features, patients are not satisfied with the case when the time and process of medical treatment are getting longer. It is surveyed that consumer were satisfied with the motivation to visit a hospital and the insurance type in patient's feature and so were the medical department and the factor of the degree of the expectation in disease's feature. Sixth, according to analysis based on the survey, patients would join again a hospital when they get satisfaction from the medical care and also they want to come again regarding to doctor's capability. For example, when doctors are old, have a good carrier and much experience, patients would come again. As seen from the above, consumers are usually satisfied with the medical treatment more than that they expected before. They would intend to use again when they get satisfaction from the medical care provided at a hospital. Patients and consumers highly expect good attitude as well as capacity from medical doctors and they are also generally satisfied with those things. Therefore, in order to increase the degree of consumer's satisfaction and their intention to come again, the hospital staff would have to commit themselves to achieve high quality service continuously and would have to make an effort to offer the finest quality service.

• The Korean Nurse
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• v.36 no.1
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• pp.59-76
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• 1997

The purposes of this study were to identify the contents and satisfaction level of the patients received home care service, and to compare the differences of the contents by the characteristics of the patients. Seventy eight patients received home care service from 1st Jan. to 30th Sept., 1996 were data-collected to analyze the contents and outcomes of home care service. Sixty-nine patients currently receiving home care service were participated to evaluate the satisfaction level of home care service. The data were analyzed using mean, standard deviation, $x^2$ test, and ANOVA by SPSS $PC^+$ program. The findings of this study were as follow : 1. The contents & outcomes of home care service 1) The mean age of the subjects was 64.4 years: 58% of them were female. Those who living in Seoul were 83% and the rest of the subjects was living in Kyung-Gi. 2) The subjects who had one diagnosis were 41%. Over 60% of them had the disease of neurologic & sensory system. 3) The mean number of visit was 6. Only one visit was 22%. The mean time of care was 79 minutes. Duration of visit from 31 minutes to 60 minutes were 47 %. The subjects who terminated the visit because of death were 67.3%. 62% of the persons who referred them to the home care service were nurses. 4) The pain after the service was more relieved than before. The amounts of intake, the degree of bed sore, edema & fracture after the service were more improved than before. Health status after the service was improved in general. 5) There were significant differences between initial and last conscious level in tracheostomy care & oxygen inhalation care. There was significant difference between initial and last degree of activity in blood sugar check. 6) There were significant differences on the number of visit in assessment of the status, evaluation & observation, vital sign check, skin care, injection, medication, bed sore care, colostomy care, relaxation therapy for pain relief, patient education, family care, exercise therapy, position change, supply of disinfected equipments and infection control. There were significant differences on visiting time in nasogastric tube care, drainage tube care and oxygen inhalation care. 2. The satisfaction level of home care service 1) 50% were male. Over 60 years of the subjects was 61 %. Those who living in Seoul were 82%. 2) The subjects who had one or two diagnosis were 32% respectively. 55% of the persons who referred them to the home care service were nurses. 3) Total level of satisfaction of home care service was very high. 4) The older the age, the higher the satisfaction level. The larger the number of visit, the higher the satisfaction level. 5) The subjects who were in cloudy state were higher level of satisfaction than in alert or coma state. The subjects whose activity were normal or who needed assistance were higher level of satisfaction than bedridden or immobilized subjects. These findings suggested that the patients had substantial need for posthospital care. They tended to be elderly and to have experienced the wide range of health problems associated with aging, chronicity, including limitations in activities, and other serious health problems. So, the nationwide home care systems beyond the limit of demonstration program by local association and the development of the effective financial system of home based health care are necessary for the clients who are in need of home care.

• Journal of radiological science and technology
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• v.37 no.2
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• pp.93-100
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• 2014

Recently the development of portable digital wireless imaging system, which acquires digital radiation images by using wireless LAN telecommunications function in an easy and fast way, provides lots of convenience for people. Considering the characteristics of portable imaging tests on emergency and critical patients, this study aims to suggest guidelines for Digital wireless detector by evaluating the effect of de-centering of focus-grid and displacement of subject in detector on the quality of image. The equipments used for this study were Elmo-T6 Digital Mobile X-ray system (SIMAZU Corp.), el' Tor ($14{\times}17$ "Wireless detector), Grid (10:1) and Chest & head phantom. After acquiring post-processing image according to dose increase and de-centering image of grid-focus and head phantom displacement image, this study compared, analyzed and evaluated these images by using a digital image analysis program by Image J. In the change of images based on dose increase, images were rough in the dose of 0.5 mAs, while there was no difference among images in the proper dose of 1~2 mAs and, especially from 2.5 mAs, average value of pixels radically decreased, affecting contrast. Over 3 mAs, contrast dropped due to saturation phenomenon of lungs. As the result of analysis using Image J program, with the increase of displacement between focus-grid and head phantom, the frequency of low pixel value also increase, causing the outline of surface image to disappear, which in turn affects contrast. For better quality imaging, a radiographer must be aware before the time of test that the image quality can be changed based on the critical patient's posture, movement, respiration, displacement of X-ray tube and distance of imaging.